Question:
There are various situations where you may need to convert a unix timestamp to the TDateTime format and back, e.g. in a mixed environment where you access files on a Unix system or if you use a mySQL database.
How can it be done?
Answer:
The code below uses the unix start date (1/1/1970) as a TDateTime constant and multiplies (divides) with the amount of seconds per day which is 86400.
You can call the functions like this:
DateTimeToUnix(now);
UnixToDateTime(1002187414);
const
// Sets UnixStartDate to TDateTime of 01/01/1970
UnixStartDate: TDateTime = 25569.0;
function DateTimeToUnix(ConvDate: TDateTime): Longint;
begin
Result := Round((ConvDate - UnixStartDate) * 86400);
end;
function UnixToDateTime(USec: Longint): TDateTime;
begin
Result := (Usec / 86400) + UnixStartDate;
end;